Book Image

Mastering Concurrency Programming with Java 9 - Second Edition

By : Javier Fernández González
Book Image

Mastering Concurrency Programming with Java 9 - Second Edition

By: Javier Fernández González

Overview of this book

Concurrency programming allows several large tasks to be divided into smaller sub-tasks, which are further processed as individual tasks that run in parallel. Java 9 includes a comprehensive API with lots of ready-to-use components for easily implementing powerful concurrency applications, but with high flexibility so you can adapt these components to your needs. The book starts with a full description of the design principles of concurrent applications and explains how to parallelize a sequential algorithm. You will then be introduced to Threads and Runnables, which are an integral part of Java 9's concurrency API. You will see how to use all the components of the Java concurrency API, from the basics to the most advanced techniques, and will implement them in powerful real-world concurrency applications. The book ends with a detailed description of the tools and techniques you can use to test a concurrent Java application, along with a brief insight into other concurrency mechanisms in JVM.
Table of Contents (21 chapters)
Title Page
About the Author
About the Reviewer
Customer Feedback

Second example - executing periodic tasks

In the previous examples with executors, the tasks were executed once, and they were executed as soon as possible. The executor framework includes another executor implementation that gives us more flexibility about the execution time of the tasks. It's the ScheduledThreadPoolExecutor class that allows us to execute tasks periodically and to execute tasks after a delay.

In this section, you will learn how to execute periodic tasks implementing an RSS feed reader. This is a simple case where you need to make the same task (reading the news of an RSS feed) at a certain time. Our example will have the following characteristics:

  • Store the RSS sources in a file. We have chosen news about the world from some important newspapers such as The New York Times, the Daily News, or The Guardian.
  • We sent a Runnable object to the executor per RSS source. Every time the executor runs each one, it parses the RSS source and converts them to a list of CommonInformationItem...